Radiotherapy, e.g. after breast-conserving surgery improves loco-regional control and survival, however at the risk of cardiac events and secondary cancer of the lungs and the non-treated breast. In view thereof, there is an increased tendency for treating patients in prone position instead of the traditional treatment in supine position. Indeed, the treatment in prone position can result in a reduced acute toxicity and a reduced risk of radiation-induced cardiac toxicity, lung and contra-lateral breast cancer. Prone positioning exploits gravitation to obtain its radio-physical advantages. The downwards hanging breast elongates vertically, narrows horizontally, stretches skin folds and moves target tissue away from radiation-sensitive organs, mainly the heart and lungs.
A number of devices for prone breast irradiation is currently available. A first category includes prone breast boards, which are placed on top of the standard treatment couch surface in support of the patient lying prone. A further category of devices includes prone breast couches, which replace the standard treatment couch blade or part thereof. Prone breast boards or couches feature a specifically shaped aperture, thereby allowing the breast to hang freely below the board or couch surface.
Examples of such prior art breast couches are disclosed e.g. in PCT application WO20013/139713 and US patent application US 2013/019876. Both breast couches however require that at least the ipsilateral arm at the side of radiation treatment of the patient is positioned above or behind the head, which causes a lot of discomfort for patients having undergone breast or lymph node surgery.
In practice, the use of currently available prone breast boards and prone breast couches is limited to patients requiring breast-only irradiation. However, about one third of the patients require irradiation of the breast and the regional lymph node regions. For these patients, the above-mentioned prone breast boards or couches are unsatisfactory. US patent application US2004/105477 for example discloses a breast board, having one or two apertures configured to for the breast(s) to be pendently suspended therethrough, with no radiation beam access to the lymph nodes. Furthermore, such a board may severely restrict the range of favourable beam access and disturb radiation build-up needed to protect the skin.
Thus, there is a need for radiotherapy breast boards or couches which mitigate one or more of the problems stated above.